As a type of the image forming apparatus, a toner container (a toner bottle) is known which is provided in a manner such that it can be detachably mounted in an image forming apparatus body, which toner container is a tubular powder material container which contains toner (a powder material) for replenishment, for example. Many of such tubular toner bottles mainly include an elongated tubular container body and a cap. The container body, which has an opening formed on the one end side in a longitudinal direction, is configured such that contained toner is conveyed toward the opening. The cap, which is provided such that it covers the opening of the container body, has formed an internal space (a temporary containing space) which temporarily contains toner which is fed in from inside the container body via the opening. Moreover, the cap has formed on a side face in the longitudinal direction of the container body a discharge hole which discharges, to outside, toner within the internal space. Furthermore, on the discharge hole of the cap is provided a shutter member. This shutter member causes the discharge hole of the cap to be blocked from the outside of the cap when the toner container is not mounted in the image forming apparatus body. This makes it possible to prevent toner from leaking out of the discharge hole when the toner container is not mounted in the image forming apparatus body. On the other hand, when mounted in the image forming apparatus body, the shutter member causes the discharge hole of the cap to be open, making it possible to discharge the toner within the toner bottle from the discharge hole to replenish a developing apparatus (powder material using unit) of the image forming apparatus body with toner.
For configurations of conveying the toner inside the container body from the opening of the container body to the cap, various configurations are widely adopted such as, for example, a configuration in which a spiral-shaped conveying projection is formed on an inner wall face of the container body, and the container body is rotationally driven with the longitudinal direction as a rotational axis to convey the toner; a configuration in which a conveying member such as a conveying screw is provided inside the container body to convey the toner with driving of the conveying member, or a different known configuration.
In such a powder material container, when a container of a powder material such as toner is left for a certain period in a relatively high temperature environment (a warehouse, etc.) with the powder material such as the toner contained inside, for example, the powder material which is contained therein coheres, leading to reduced mobility of the powder material such as the toner, etc. More specifically, in the above-described powder material container, where the container body is elongated and a discharge hole is formed on a cap provided on an opening in the one end side in the longitudinal direction of the container body, when the powder material container is stored in a position such that it stands up with the cap facing downward, the weight of the powder material which is piled up high within the container body acts on the powder material within the cap, so that the powder material within the cap firmly coheres. As a result, the discharge hole which is provided at the cap is blocked with the powder material which is firmly cohered, so that, when the powder material container is mounted in the image forming apparatus to use the powder material container, a situation occurs in which replenishment, with the powder material from the discharge hole, of the image forming apparatus body is prevented, or there is a discharge failure.
A toner container disclosed in Patent document 1 adopts a configuration which makes it possible to improve on such a discharge failure. More specifically, in the toner container, when mounted in the image forming apparatus with the cap fixed, the container itself is rotationally driven with its longitudinal direction as the rotational axis to convey toner within the container body to the cap. At the opening of the container body is fixed an agitating member which extends into inside the cap along the longitudinal direction of the container body. A tip of the agitating member is shaped such that it builds over an inlet face of the discharge hole facing a side face inner wall of the cap. With such a configuration, the toner which is firmly cohered and which blocks the inlet face of the discharge hole is disentangled with the tip of the agitating member which is driven with a rotational drive of the container body, easing the cohering of the toner that prevents the toner from being discharged from the discharge outlet, making it possible to improve on the discharge failure caused by the cohered toner.
Now, the present inventors have found, as a result of research, a problem that the discharge failure caused by the cohering of the toner may not be suppressed sufficiently even with the toner container as disclosed in Patent document 1.
A space which corresponds to a side face wall thickness of the cap exists inside the discharging hole formed on the side face of the cap, or, in other words, between an inlet face which faces an inner wall face of the side face of the cap and an outlet face which faces an outer wall face of the side face of the cap. A tip of the agitating member in the toner container disclosed in Patent document 1 may disentangle the toner which blocks the inlet face of the discharge hole, but may not disentangle the toner which is cohered inside the discharging hole. When the side face wall thickness of the cap is sufficiently thin, a wall of the toner inside the discharging hole that prevents the toner from being discharged from the discharging hole is thin, so that there may be a case such that an impact arises which is not sufficient to produce a discharge failure. However, in terms of maintaining the strength of the cap, a certain amount of wall thickness is necessary for the side face of the cap for securing the strength of the cap, etc., so that the wall of the toner which coheres inside the discharging hole becomes thick, causing a discharge failure.
However, this problem is not limited to when the powder material is the toner.